1. Field of the Invention
The present invention relates to modular and manufactured residential and commercial buildings, and more particularly, to a foundation support system for such residential and commercial buildings.
2. Description of the Related Art
Modular manufactured residential and commercial buildings have become increasingly popular in recent years. As the cost of new construction continues to rise, the relatively lower cost of modular manufactured residential or commercial buildings are attractive to many buyers. Over the past many years, much has changed in the design of modular manufactured residential and commercial buildings. Particularly in their size and weight. Whereas manufactured buildings were essentially limited to the trailer-house type of structures, now, more traditionally-styled manufactured buildings having large structural elements are available and in use. Throughout this specification, reference is often made to "modular" or "manufactured" buildings, structures or homes. It should be appreciated that such reference is intended to include both the "trailer-house" type structures on wheels, and the more permanent "traditionally-styled" manufactured buildings, structures or homes where the modular sections are trucked to the building site on flatbed trailers.
The evolution of the manufactured residential and commercial buildings and their increase in size and weight has led to several problems in the design of a foundation support system capable of providing the necessary strength and stability to support the structures. For example, previous foundation support systems for manufactured buildings are characterized by a plurality of dry-stack concrete blocks positioned on concrete pier footings. The concrete pier footings are designed to bear below the frost depth to eliminate heave problems associated with freezing and thawing cycles of the soil. The concrete blocks rest atop the concrete pier footings and are disposed between the concrete piers and the main support beams of the manufactured building.
Typical dry-stack concrete block foundation support systems are not designed to withstand the loads required by modern manufactured buildings and often crack or break under the higher stresses. As such, if a dry-stack block foundation support system is to be used, many concrete piers and concrete blocks are required to adequately support modern manufactured buildings. For example, a standard 28.times.60 foot manufactured residential home will require approximately sixty concrete piers and at least twice that many concrete blocks. The need for such a large number of piers and concrete blocks presents several problems. Foremost is cost. Additionally, great care must be taken to align the concrete piers and the concrete blocks thereon with the main support beams of the manufactured building. If the piers and blocks do not align with the main support beams, the concrete blocks will not properly transfer the load to the pier footings below.
Thus, there is a need in the industry for a foundation support system that can support the larger loads required by modern manufactured structures, yet requires fewer footings to properly support the structure. There is also a need in the industry for a foundation support system that can be slightly skewed or out of alignment with the main support beams of the manufactured structure, but still properly transfer the structure's loads to the footings.
Another problem with previous types of foundation support systems is that the previous systems are difficult to adjust vertically as required during installation of the manufactured building. For example, with dry-stack block foundation systems, vertical adjustment is essentially limited to shimming the main support beams of the manufactured building with respect to the dry-stack concrete support blocks. Shimming is not a precise method, and it is difficult to shim a large area while ensuring adequate surface bearing contact between the supporting surface and the shimmed members. Accordingly, there is also a need in the art for a foundation support system that easily adjusts in the vertical direction.
Another problem with previous foundation support systems is that if the concrete blocks shift or move only slightly, the blocks may end up partially resting on or against the soil. This presents a serious problem, since during periods of extreme temperature change, the soil will often heave, causing the concrete blocks partially resting on the soil to crack or break. For this reason, it is necessary that building owners frequently monitor the concrete blocks supporting their structure each spring and fall. Such damage to the concrete blocks, however, often goes undetected. Subsequently, when the concrete blocks shift or break, the structure will likewise shift, requiring a construction company or manufactured building dealer to properly reset the structure at a significant cost. As such, there is a need in the industry for a foundational support system that is not susceptible to soil heave and adequately secures the structure to the footings.
A further problem with previous foundation support systems, is that they are not capable of resisting lateral or uplift loads due to wind. Therefore, the manufactured buildings must be tied down with straps anchored into the soil. These tie-down straps are normally 12 gauge metal straps extending over the structure's main support beams or over the top of the structure and secured to anchors driven into the soil. As such, there is a need in the industry for a foundation support system that may eliminate the need for tie-down straps.
Another problem with previous foundation support systems, is that they are not capable of resisting lateral or uplift loads on the foundation support system due to earthquake loading. As such, there is a need in the industry for a foundation support system that may be used on manufactured buildings to resist earthquake induced lateral and uplift loads on the foundation support system.
It can therefore be seen that there is a real and continuing need for the development of an improved foundation support system for manufactured residential and commercial structures.